FRIDAY, Feb. 27, 2026 (HealthDay News) -- Placental vascular reactivity (PLVR) can help identify fetal congenital heart disease (CHD), according to a study recently published in Magnetic Resonance in Medicine.Vidya Rajagopalan, Ph.D., from the Keck School of Medicine at the University of Southern California in Los Angeles, and colleagues conducted a prospective cohort study to compare PLVR, the fetally mediated placental response to transient changes in maternal carbon dioxide (CO2) quantified using blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI), in pregnancies with and without fetal CHD. As pregnant women followed audio-visual breathing cues, placental BOLD MRI was acquired concurrently with maternal end-tidal CO2 (EtCO2) for seven to eight minutes. A coherence-weighted general linear model was used to compute PLVR between MRI signal and EtCO2 stimulus. Global PLVR was the mean of voxel-wise PLVR across the placenta.A total of 103 pregnant women were included in the study: 31 with fetal CHD and 72 with healthy fetuses. The researchers found that compared with the non-CHD group, PLVR was lower in CHD (0.024 ± 0.02 versus 0.03 ± 0.04 ΔBOLD/mmHg CO2). In CHD versus non-CHD groups, maternal diabetes had differential effects on PLVR."Measuring placental function in real time gives us a window into how these babies are developing," Rajagopalan said a statement. "That's especially important in congenital heart disease, where the placenta may play a key role in supporting brain development."Abstract/Full Text (subscription or payment may be required).Sign up for our weekly HealthDay newsletter